The timely processing of invoices and payments is an essential tool to modern business. A variety of businesses customarily receive mail in large quantities and in bulk form. A number of devices have been developed to handle bulk mail to facilitate efficient processing of the contents, so that payments can be deposited rapidly. Such devices extract the documents from the envelopes, then reorient and sort the documents. An example of a comprehensive apparatus of this general type is the Opex System 150, which is manufactured by Opex Corporation of Moorestown, N.J.
When sorting documents, it is desirable to detect documents containing ferrous objects such as staples and/or paper clips that may damage the apparatus and/or the documents if processed. Therefore, it is desirable to separately sort documents having a paper clip or staple so that the documents can be processed manually.